Apparatus for drying paper.



B. R. ANDREWS da G. J. MERRILL. APPARATUS FOR DRYING PAPER.' APPLIoATIoN FILED MAY 7, 1914.

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BERNARD E. ANDREWS, E NEWTON, MASSACHUSETTS, AND CABLE J. MERRILL, or

PORTLAND, MAINE.

APPARATUS FOR'DRYING PAPER.

Specification of Letters Patent.

Patented Jian.. 5, i915.,

Application led May 7, 1914. Serial N o. 836,841.

A State of Maine, respectively, have invented an Improvement in Apparatus for Drying Paper, of which the following description,

in connection with the accompanying drawing, is a specilicati'on, like characters on the drawing representing like parts.

This invention relates to drying apparatus which is especially adapted for use in drying or facilitating the drying of a web of material as it passes over a plurality of rolls, cylinders, or other lsupporting members. Vhile our invention is capable of use in connection with a variety of drying devices adapted for drying a web as it thus passes over supporting members, .yet we have herein chosen to illustrate it as it would be applied to an apparatus for drying a web of paper as it passes through-a palperinaking machine. It will be understood, however, that the invention is not confined to use in drying paper and that the invention is shown herein as appliedto a papermaking machine for illustrative purposes onl f.

Iii the manufacture of paper it is customary to dry the web of paper as it comes from the squeeze rolls and before it is deliveredcto the calendering rolls by passing the paper web over a plurality of heated cylinders, said cylinders being frequently so arranged relative to each other that inpassing ovei' them the web forms a plurality of pocket-like spaces between adJacent rolls. One familiar way of arranging the rolls is to place them in two rows, one above the other and in staggered relation so that one series of pocket-like spaces is formed be neath the rolls of the upper set and between the adjacent rolls of the lower set, and another series of pocket-like spaces is formed above the rolls of the lower set and between the adjacent rolls of the upper set.

In the operation 'of a drying machine of this type the heat of the cylinders causes large volumes of steam to be driven ofi' from the web of paper as it is passed thereover, and to facilitate the drying operation it has been proposed to place nozzles in the various pockets from which drying blasts of air are delivered against the web forming the sides of the pocket, said blasts of air being produced from a suitable Vfan or blower.

A paper-making machine is usually provided with a considerable number of drying cylinders, thus forming a corresponding number of pockets, and in order to furnish to the nozzle all. the air required to dry the `web a blower or fan of considerable size and one requiring considerable power is necessary. Moreover, where the entire current of drying air is delivered from a blower it is difficult to so distribute the air over the web of'paper as to produce an even drying in the web, this beiig partly due to the fact that the drying operation produces considerable volumes of steam which collect in the pockets and preventthe center portion of the web from drying as rapidly as the edges thereof. The, drying of the web .tends to shrink it somewhat and where the edges-dry faster than the center the corresponding shrinkage at the edges is very apt to cause the web to break.

We have endeavored to provide a novel apparatus and method of drying/web material by which such material, and especially a paper web, can be dried evenly and rapidly by drying currents of air and with the expenditure of a considerably less amount of power than is necessary where all the drying blast of air is delivered from aV blower or fan. Vile accomplish this object by delivering to each of the pockets a blast of air in such a way that it will induce a t current of room air to pass through the pocket from one end to. the .otherV whereby the web forming the walls of the pocket is dried partly by the action of the blast of air and partly by the action of the induced current of air. `In the 4preferred embodiment of our invention we provide forfsubjectiiig a portion of the area of the web to the combined action of the drying blast or current of air delivered from a nozzle by means of a blower and thel current of room air induced bv said first-named cui-rent of air, and the rest of the area of the web to the action of said induced current of room air alone. By this means an. even drying of the web is secured with the use of a comparatively small forced draft. In the preferred embodiment of our invention, `we also provide a nozzle device by which a currentf inducing, drying air current is delivered portion of the web not .exposed to the current-inducing air current. The combination i of these two air currents operates to rapidly dry the web with the expenditure of minir1.0.

mum power. The relation between the nozzle and the walls of the pocket is such `that said nozzleand pocket constitute a sort lof `injector' by which a small current of air i delivjered from.r the nozzle induces a. comparatively large current of room air through the pocket thereby providing for securing i :the desired ra iddrying with a minimum expepditure o I power. Moreover, in arl v ranging our device, we propose to deliver `the currents into the pockets from the front of the machine and in such a way that the induced clrrents will also enter the pockets from therfront of the machine. As a' lresulte y the steam'and vapor is carried oiit at the backof the machine, thus leaving thefront of the machine where the opera-torstands comparatively free from steam.

To facilitate a clear understanding of ourl invention and its mode of application and operation we have illustrated` in the accompanying drawings and we will now describe that portion of a paper-making machine uwhich effects the drying o'fthe paper web and which has applied thereto a practical mechanical embodiment of the invention, but we desire to repeat our statement above to the edect that our invention is'not limited in its application and use to a paper-drying machine, but is equally well adapted'for use in connection with any drying apparatus for drying a web which passes over a plurality of rolls or cylinders.

In the drawings, Figure 1 is a more or less "diagrammatic, view of the side elevation of the drying rolls of a paper-making machine showing our improvements applied thereto Fig. 2 is an end view of Fig. 1; Fig. 3 is an enlarged section through one of the upper pockets on the line Fig. 1, showing the way in which the two currents of air enter and pass through the pockets; Fig. 4 is a side view of a practical nozzle capable of carrying out our invention; Fig. 5 is a section .on the line y-y, Fig. 4; Fig. 6 is an enlarged section through one of the felt pockets on the line (1 -a, Fig. 1, showing the manner inwhich the air currents are utilized for dryingthe felt apron.

- We have shown at 1 and 2 a plurality of cylinders, which may be the drying cylinders of a paper-making machine, and over which travels the web 3 that is to be dried. In the construction shownin Fig. 1 the cylinders 1 and 2 are arranged in two rows, one above the other, the cylinders of the upper row being designated 1 and those of the lower row being designated 2, and the web 3 passes over these cylinders successively. This arrangement of cylinders and web presents a plurality of pocket-like spaces 4 beneath the upper cylinders 1 and between the adjacent cylinders 2, and another series of pocket-like spaces 5 above the lower cylinders 2 and between the adjacent upper cylinders 1, the walls of these pocket-like spaces being formed of the web 3 as it is passing from one roll to another. .We will herein`L after refer to these pocket-like spaces as pockets.

It is the common practice to employ a felt apron which travels uniformly with the cylinders and which serves. to hold the web of paper on the cylinders, thus tending to prevent it from becoming ru tured, and we have herein shown at 6 and two such felt aprons, the apron 6 coperatino' with the lower cylinders 2 and the apron F coperating with the upper cylinders 1. These felt aprons are shown as passing over direction .rolls 8 situated between the various cylinders. The parts thus far described are such as are commonly found in paper-making machines.

In applying our improvements to a machine of this type we rovide means situated exterior to the pockets 4 and 5 and adapted to deliver intov them two currents of air, one a current-inducing drying air current which is forced over a certain portion of the area of the web and another a current of room air induced by the first-named current and which is passed over the remaining portion ofthe web, the two air currents combining to dry the web evenly. The currentinducing air current isdelivered into the pockets from nozzles 9 which are situated exterior to the pockets and are preferably located on the front of the machine. W'e will preferably employ one nozzle `for each pocket, although this particular arrangement of nozzles is not essential. Each nozzle is connected by a branch pipe or conduit 10 with a main conduit 11 which leads to a suitable/blower or air-forcing mechanism, and we will preferably use two such mains, one situated above and the other below the drying cylinders. The'main situated below the drying cylinders is placed in the pit 12 which is usually provided underneath the drying cylinders 1 and 2. We have shown the upper main 11 as supplied with air through a supply pipe 13 which connects to the supply pipe 14 which supplies air to the lower main 11, the supply pipe 14 leading to a suitable blower or air-forcing mechanism. The nozles 9 are designed so as to deliver a current-inducing air current 15,in dicated by the full line arrows, against the web 3 forming the wall of the pocket at a point intermediate of the edges of the web, this l the web and .evenly dried so that there current 15 preferably being so directed that it will strike the web 3 at somewhere near its central portion. Furthermore, this current is directed against the web `3 at an angle thereto, and in such a direction as to induce a current 16 of room air into and through the pocket, said current being indicated by the dotted lineA arrows. We propose to induce a current-inducing air current against each wall of each pocket so that the web forming each of said walls will be acted upon not only by the current-inducing airv current 15, but also by the induced air current 16,as shown best in F ig. 3. inducing air current 15 does not of itself act on the web at the entering end of the pocket but only acts portion of the pocket and the exit end thereof. rllhe induced current 16 of room air acts on the web at the entering end of the pockets and then commingles with the air current 15 and both air currents act on the web from the central portion of the pocket to the opposite edge of the web. This is plainly indicated in the diagram shownin 3.

compar. tively small current-in ucing air current 15 is suiiicient when properly directed to induce a current 16 of room air,

as only a portion of the voldrying current or air-forcing mechanism, the remainder of the drying current being the induced current 16, a considerable less amount of power is required to operate the blower than where all of the drying current is delivered from the blower. oreover, we find that by delivering the current l5 against the central portion of depending on the induced current 16 of room air for drying the edge of the web adjacent the nozzle, the web will be will be no danger of its becoming torn or ruptured because of more Lrapid drying on the edge than in the center. rlhe wallsiof the pocket together with the nozzle 9 form a sort of injector by which a small current of air delivered from the nozzle induces a suiiicient current of room air through the pocket to eect the desired drying of the web.

With the arrangement of cylinders shown in Fig. 1 it will be seen that the portion of the web between any two cylinders 1 and 2 forms one wall of two adjacent pockets 4 and 5, and since two drying currents of air are introduced into each pocket and against each wall of each pocket, it follows that both sides of each portion of web which is free from the cylinders 1 and 2 and extends from one cylinder to the other is acted upon by the drying currents. This arrangement still further facilitates the drying operation.

The two current-inducing air currentsV l5 for each pocket can be delivered from a single nozzle by employing a properly con 'sential to our invention.

or openings 17 situated The current-- on the web between the centralA j t e attend strueted nozzfe and Illustrated a nozzle pose, although this in the drawings we havedesigned for this purconstruction is not es- The nozzle herein shown is provided with two discharge ports other and adapted to deliver two diverging air currents l5 herein illustrated. A convenent form of purpose is one provided in its discharge end with the `i/-shaped deflector l8 which forms a separation between the two discharge ports and serves to give said ports a divergent direction. We may if desired provide the nozzle with means, such as the plates 19, 'at each side thereof for decreasing slightly the cross-sectional area of the nozzle directly back of the defiector 18, these plates 19 cooperating with the deiiector 18 to more positively insure that the currents of air 15 Will be delivered infthe inclined direction desired.

We propose to arrange the nozzle 9 on the front side of the machine, that is, on tha Side of the machine at which the attendant is situated.

from the apparatus during the drying process will be drawn through the pockets by the air currents and delivered therefrom on the opposite side of the machine from which ant is located. The attendant isV thus situated at all times in air which'is. comparatively free from steam and vapor.

e have also designed the nozzles herein shown so that they will not interfere materially with the operation of handling the paper web to guide it from one roll to anat an angle to each f n ozzle adapted for this other in case the web breaks and it is necessary to thread an end of variou-s cylinders.

The branch pipes l0 will preferably be placed between the ends of the cylinders 1 and 2, and the front side of the frame 21 in which the cylinders are sustained and said pipes are so designed as to interfere as little as possible with any necessary manipulation of the paper. Each nozzle 9 will preferably be" located substantially centrally of its pocket, and each branch pipe 10 is provided with the vertical' portion 20 to which the nozzle is secured; with the inclined portion 22 extending across the end of the drum and with the vertical portion 23 connecting to the main 11, the vertical portion being situthe web through the ated between adjacent cylinders 2, as shown. f

his arrangement is one in which the branch pipes 10v and nozzles are so situated that they do not interfere with the operator introducing his hand into the pocket to feed an end of the web from one cylinder to the next one. We will preferably employ a nozzle which can be collapsed more or less when not in use thus permitting it to be carried still more out of the way than when in its 1 from Fig. 1- that o erative position. In the drawing we have own the nozzle as supported` on a telescopic pipe section 26 which telescopes into the upper end of the portion orv the branch pipe 10. 'Ihe nozzle 9 itself is pivotally mounted on the telescopic pipe sec-- tion 26, as shown at 27, so that saidnozzle can be turned back into'line4 with the pipe section, as shownl by dotted lines Fig. 4.

This nozzle is shown as made of sheet vmetal bent into the desired shapeand is provided at its rear end with a lip-28 adapted to-,ensl gage a set screw '29qcarried1by` the upper end ofthe pipe section. The .upper side 30 of the nozzle is, curved on an arc struck :from

the pivot 27l as a center so vthat the nozzle ,n

can swing back on its axis into its inoperative position. The construction herein' shown operates also as a means for drying the felt apronsv and7, for itjwill be seen the air currents which pass through the pockets will act on the portion of each felt apron that is separated from the web of paper and passes over the rolls 8.. The air currents thus'have a drying effect not only on the web of paper but also on the felt. This is a very great advantage because it prevents the felt from becoming unduly wet.

In the construction shown inFig. 1 the felt aprons 6 and 7 pass over direction A pulleys 8 and said aprons have formed therein pockets 31 which are commonly referred to in this art as the felt pockets.- We have provided herein means for delivering air currents through these felt pockets to assist in drying the felt, and the air cur rents which thus pass 4through the felt pockets are of the same nature as those which pass through the pockets 4 and 5, that is, they areformed from a current-inducing air current commingled with .an air current induced by the irst-named current. In order toisecure this effect, we provide each of the branch pipes 10 with a nozzle 32 directed toward the adjacent felt pocket 31, said nozzle delivering into said pocket a current of air designated by the arrows 33. This current of air 33 induces a current of yroomair designated by the arrows 34, and

the two combined currents passing through the pocket 31 assist in drying the felt apron.

The walls of each pocket l'together with .a paper-making machine, we do not wish to be limited to lts use 1n this connection, as it will be obvious that the principle ofthe invention may be applied to different devices where theweb to be dried passes over supports which-form in said web one orl more supported thereby,

pockets arranged so that the injector action A above described can besecured. We'cla1m:

1. In a dryingapparatus, the combina-` air .into and through the "pocket over the' surface'of theweb.

2. In a device of theclass described, the

combination with a plurality of supportingmembers over which a web to be dried 1s adapted to travel and which are arranged to form a plurality of pockets in the web supported4 thereby, of a` nozzle situated at the end of and exterior to each pocket and disposed to deliver a current-inducing air current into said pocket in a direction to impinge against the web intermediate of its edges and to induce a current of room air into and through the pocket over the surface of said web.

3. In a device of the class described, the combination with a plurality of supporting members over which a web to be dried is adapted to travel and which are arranged to form a plurality of pockets in the web of means situated at the end of Aand exterior to each pocket to deliver thereinto ,and over the surface of the web forming the walls of the pocket remote from said means a current-inducing blast of air and to induce a currentof room` air over .the portion of the web adjacent said means.

4. The stepl in the method of drying a.

web which is traveling over supporting members arranged to form pockets in said web which consists in subjecting a portion of the area of the web tothe action of a blast of drying air and the rest of said area to the action of a current of room air induced by the blast of air.

5. zThe steps in the process of drying a web of material which is traveling over a plurality of cylinders arranged to form pockets in the web which consists in delivering a burrent of air into each pocket against the web forming the wall thereof at apoint intermediate of the edgesof the web and at an angle thereto and inducing a current of room air into the pocket over the surface of the web not affected by the firstnamed current of air.

6. In an apparatus of the class described, the combination with upper and lower cylinders over which a web is adapted to travel thereby forming a series of pockets beneath the upper cylinders and between the adlllll Macnee i jacent lower cylinders, of means to deliver into the pockets current-inducing currents of dry air in a direction to impinge against the web foaming the sides of the pockets at points between the edges of the .web and to induce currents of room air across the portion of the web not exposed to the currentinducing air current.

7. In an apparatus of the class described, the combination with upper and lower cylinders over which a web isadapted to travel thereby forming a series of pockets beneath the upper cylinder and between the adjacent lower cylinders, of means situated entirely outside of the pockets to deliver into the pockets current-inducing currents of dry air in a direction to impinge against the web forming thesides of the pockets at points between the edges of the web and\t0 induce currents of room air across the portion of the web not exposed to thecurrentinducing air current.

8. In an apparatus for drying', the combination with upper and lower cylinders over which a web is adapted to travel thereby forming a series of pockets above the lower cylinders and between the adjacent upper cylinders, of means to deliver into the pockets current-inducing currents of' dry air in a 'direction to impinge against the web. forming the sides of the pockets at points between the edges of the web and to induce currents of room air across the portion of the web not exposed to the current-inducing air current.

9. In an apparatus for drying, the combination with upper and lower cylinders overwhich a web is adapted to travel there? by forming a series f pockets beneath the upper cylinders and above the lower cylinders, of a nozzle situated at the end of eachv pocket A exterior `thereto and having two divergent discharge openings arranged to direct a current of air issuing therefrom against the web. forming the sides of the pockets at points intermediate of the edges of the web, and means Ato supply air under pressure to said nozzles.

l0. In a device of the class described, the combination with supporting members'over which a web to be dried is adapted to travel and which are arranged to form pockets in saidl web, of an air supply pipe leading to each pocket, and a nozzle connected to each air supply pipe but situated exterior of the corresponding pbcket and provided lwith means to deliver an air current against the sides of the pocket at an angle thereto, each nozzle having a telescopic engagementwith uwaw m zle pivoted to each supply pipe and adapted to be turned from its operative position directly toward the pocket into its inoperative position in alinement with the supply pipe.

12. In a drying apparatus, the combination with a plurality of supporting members over which a web to be dried is adapted to travel and which are arranged. to form one or more pockets in the web supported thereby, of means to deliver a current-inducing air current into each pocket and to induce a current of room air into and through the pocket over the surface of the web.

13. In a device of the class described, the combination with a plurality of supporting members over which a web to be dried is adapted to travel and which are arranged to form a plurality of pockets in the web supported thereby, of means situated adjacent one end of each pocket to deliver thereinto and over the surface of the web forming the walls thereof remote from said means a current-inducing blast of air thereby to induce a current. of room air over the portion of the web adjacent said means..

14. In an apparatus of the class described, the combination with means to support a ltraveling web to be dried and arranged to form a pocket in said web, of means to deliver a current-inducing air current into said pocket Afrom one end thereof and in a direction to induce a current of room air through said pocket from said end to the other end thereof whereby the web will be '100 dried partly by the induced current of room air and vpartly by ythe current-inducing air current.

.In testimony whereof, we have signed our names to this specification, 1n the presence 105 of two subscribing witnesses.

BERNARD R. ANDREWS. CARLE J. MERRILL.

Witnesses:

Louis C. SMITH, THOMAS J. DRUMMOND. 

